In a study published in the Journal of Advanced Concrete Technology, researchers from the University of Tokyo collaborated with industry engineers to develop a new device that can measure carbon dioxide absorbed in concrete more easily and in a third of the time as current approaches.
A multistep process all rolled into one. This new device (right), called the concrete thermal gravimetry and gas analyzer, can carry out the same process in one-third of the time of current methods (left). Image Credit: 2024 I. Maruyama, K. Noritake, Y. Hosoi, and H. Takahashi
The box-like device, known as the concrete thermal gravimetry and gas analyzer, heats concrete samples to over 1,000 degrees Celsius, causing the CO2 inside to be released and quantified.
This new technology is simpler, more accurate, and easier to use than the current methodology, which entails a time-consuming and laborious procedure of breaking concrete samples into powder for sampling. The researchers believe it could contribute to CO2 trading in the future, as the concrete and cement industries attempt to offset their emissions as part of global greenhouse gas reduction targets.
Concrete is everywhere. People live in it, walk on it, and even create films and songs about it. This tough and resilient material is a staple material in construction projects throughout the world, having been used since ancient Rome. But it is a mixed bag. On the one hand, the production of concrete, including one of its essential elements, cement, releases a significant quantity of greenhouse gases.
Cement manufacture is estimated to account for 5–8 % of total CO2 emissions from human activities to date. However, CO2 could currently be stored in concrete using carbon capture, utilization, and storage technologies.
Achieving “net zero,” in which the quantity of CO2 removed from the atmosphere equals the amount generated, has become a cornerstone of worldwide strategies addressing global warming. However, to do so, one must first understand what causes greenhouse gas emissions, in what quantities, and how much can be eliminated using various strategies.
Until now, determining how much CO2 has been properly absorbed in concrete was a lengthy procedure. A cylindrical block, about 10 cm in diameter and 20 cm in height would be crushed so that it could not react with the air (which would alter the findings). Then it went through a difficult and time-consuming procedure to become a fine, uniform powder, from which a small sample was extracted for chemical analysis.
This laborious procedure could be avoided, thanks to a new device created by University of Tokyo researchers in collaboration with engineers from industry.
We developed a new machine which can measure how much CO2 is fixed in concrete or cementitious material without having to crush it. Until now, there wasn’t a simple method to measure the amount of CO2 fixed in concrete, but with this device, we can shorten the time it takes to measure CO2 and increase the accuracy of the measurement.
Ippei Maruyama, Professor, Department of Architecture, Graduate School of Engineering, University of Tokyo
The device is used to heat a specimen block to 980 degrees Celsius. Gases, like CO2, are released from the block when it heats up and can be measured. The amount of time the concrete can react with the air is limited by this new approach, which takes around one-third of the duration of existing techniques.
The findings demonstrated that even in cases when CO2 was not evenly distributed throughout the block, a reliable measurement could be obtained.
Researchers at the University of Tokyo designed the device’s concept and parts, which were then constructed by engineers at Rigaku Corp. It was subsequently verified by researchers from the University of Tokyo and Taiheiyo Consultants Co., Ltd.
Maruyama concluded, “This device requires a suitably large space and special safety considerations, so for now, there are some limitations to its application. However, after further tests, we hope to make this device commercially available, so that it can contribute to sound emissions trading in the concrete sector and support global efforts to reach carbon neutrality.”
Journal Reference:
Maruyama, I., et. al. (2024) Development of a Large-scale Thermogravimetry and Gas Analyzer for Determining Carbon in Concrete. Journal of Advanced Concrete Technology. doi:10.3151/jact.22.383